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    Length: 2295 (0x8f7)
    Types: TextFile
    Names: »nshpopen.c«

└─⟦52210d11f⟧ Bits:30007239 EUUGD2: TeX 3 1992-12
    └─⟦af5ba6c8e⟧ »unix3.0/DVIWARE.tar.Z« 
        └─⟦ca79c7339⟧ 
            └─⟦this⟧ »DVIware/laser-setters/dvi-to-ps/maketd/nshpopen.c« 

TextFile

/*
 * @(#)popen.c	4.5 (Berkeley) 7/6/84 
 * Modified from 4.2, 2.9 BSD popen by Stephen Uitti, PUCC, Nov '85 
 * Doesn't invoke shell, saving time, becoming more secure. Calls 
 * breakargs to break line into command line arguments, delimited by 
 * white space, but ignores globing and quoting characters.  For
 * use where you don't need shell meta character expansion or filename
 * globbing. 
 */
#ifdef pdp11
#include <sys/types.h>
#endif
#include <stdio.h>
#include <signal.h>

#define	tst(a,b)	(*mode == 'r'? (b) : (a))
#define	RDR	0
#define	WTR	1
#define SPC '\040'		/* ascii space */

static int popen_pid[20];
extern char **environ;
char  **breakargs();

/* no-shell popen */
FILE   *
nshpopen(cmd, mode)
char   *cmd;
char   *mode;
{
	int     p[2];
	int     myside, hisside, pid;
	char  **elist;		/* the execv list */

	elist = breakargs(cmd);
	if (pipe(p) < 0)
		return (NULL);
	myside = tst(p[WTR], p[RDR]);
	hisside = tst(p[RDR], p[WTR]);
	if ((pid = vfork()) == 0) {
		/* myside and hisside reverse roles in child */
		close(myside);
		if (hisside != tst(0, 1)) {	/* 0, 1 => stdin, stdout */
			dup2(hisside, tst(0, 1));
			close(hisside);
		}
		execve(elist[0], elist, environ);
		perror("execv");
		_exit(1);	/* bombed execv, child dies */
	}
	free(elist);		/* discard the broken args */
	if (pid == -1) {
		close(myside);
		close(hisside);
		return (NULL);
	}
	popen_pid[myside] = pid;
	close(hisside);
	return (fdopen(myside, mode));
}

/* close for nshpopen */
int    *
nshpclose(ptr)
FILE   *ptr;
{
#ifndef	pdp11
	int     child, pid, status, omask;

	child = popen_pid[fileno(ptr)];
	fclose(ptr);
#define	mask(s)	(1 << ((s)-1))
	omask = sigblock(mask(SIGINT) | mask(SIGQUIT) | mask(SIGHUP));
	while ((pid = wait(&status)) != child && pid != -1)
		 /* empty */ ;
	(void) sigsetmask(omask);
	return (int *) (pid == -1 ? -1 : status);
#else				/* 2.9 BSD, at least */
	register f, r, (*hstat) (), (*istat) (), (*qstat) ();
	int     status;

	f = fileno(ptr);
	fclose(ptr);
	istat = signal(SIGINT, SIG_IGN);
	qstat = signal(SIGQUIT, SIG_IGN);
	hstat = signal(SIGHUP, SIG_IGN);
	while ((r = wait(&status)) != popen_pid[f] && r != -1);
	if (r == -1)
		status = -1;
	signal(SIGINT, istat);
	signal(SIGQUIT, qstat);
	signal(SIGHUP, hstat);
	return (int *) (status);
#endif	BSD4_2
}